| Action Date |
Action |
Description |
DEC Staff |
| 8/2/1988 |
Update or Other Action |
Operable Units' source areas that correspond to RCRA SWMUs from the RCRA RFA. SD28 IS-5 Bldg. 43-410 Floor Drain. This site contains one wash rack for ground equipment. -55 gals/month of PD-680* into drain to dry well.
*NOTE TO FILE: PD-680 Each item the Govt. orders must have an N.S.N, a National Stock Number, unless the Agency gets special permission to local purchase the item. Each N.S.N. item goes out for bid and has an associated minimum specification. The specification for PD-680, aka. Stoddard Solvent, back in the 1980's and before it was for a petroleum based degreaser with a specified flashpoint. No requirement for non-halogenated existed. Besides that, because Alaska was so far from vendors that supplied the Govt., many federal agencies in Alaska purchased solvents locally. There were no qualifications on those solvents and most often halogenated solvents worked with less effort than pure petroleum distillates, so they were preferred.
NSNs ordered through the PD-680 specs had some batches with TCE, Methylene chloride, etc; it depended on who the supplier to the Govt.was at the time. So as a result between 1980 and 1983, some PD-680 batches were in fact halogenated. For historical releases it pays to be suspicious of drums that say PD-680 or Stoddard Solvent. |
Louis Howard |
| 3/18/1989 |
Update or Other Action |
Dept. of Air Force letter to Sue Curtin Black & Veatch.
Per your telephone request with Capt Godsave, we submit the following
information:
1. Storm sewer system maps for SP15, SP5/5A, SP7/10, IS-1: Attached.
2. Jet Fuel Supplier: Jet fuel is supplied per one year contracts. Presently, the majority of fuel is supplied by ARCO. Their contact person is Ms Candy Stallings, 213-486-2824. Other suppliers are Tesoro (Contact - Mr Raymond Measles at 907-561-5521), Chevron (415-944-6250), and Mapco (contact - Ms Bonnie Garner at 907-276-4100).
3. Buildings 42-400, 42-425, 43-550, 42-300, 43-410, 43-450, 32-060 floor drains: Originally, minor spillage and products operations in these facilities were washed into floor drains to dry wells. Present conditions are below. Since as-builts clear, this information may not be totally correct. 21-900, and from cleaning and from there are old and not
a. IS-1, Building 42-400: Floor drains run into two oil-water separators.
b. IS-2, Building 42-425: Sanitary sewer runs along side of building, unclear whether floor drains run into it or not.
c. IS-3, Building 43-550: Sanitary sewer runs along side of building, do not know whether floor drains run into it or not.
d. IS-4, Building 42-300: Floor drains run into an oil-water separator and then into the storm drain on the east and west side of the building.
e. IS-5, Building 43-410: Floor drains are connected to septic tank and leach fields at south side of building.
f. IS-6, Building 43-450: Floor drains probably go to the septic tank and leach pits east of the building and across the railroad track.
g. IS-7, Building 21-900: The floor drains run through sumps to remove sand and grit and dump right into the storm drain on the north side of the building. The floor drains for the mechanical room run out the south side of the building and into a seepage pit. There is also a catch basin on the south side of the building that runs into a seepage pit.
h. IS-8, Building 32-060: Although sanitary sewers run near the building, it appears that floor drains go directly to dry wells.
4. How close can wells be put to the runway? If top cover of wells are flush with the ground surface, there should not be a problem. If above ground surface and within 1000 feet of the runway, the well will require a waiver. If within 500 feet of the runway, well may also be required to be frangible.
5. If well is near the runway, can piping go underground beneath a taxiway to a treatment facility? That should not be a problem if taxiway is tunneled under.
6. What is the frost depth for Elmendorf AFB? The Building Code says 42 inches.
7. Does DRMO recycle fuel? DRMO does have a contract to recycle fuel.
8. At Site D-16, can soil at the site be used for grading? If soil is within acceptable levels for contaminants, yes. However, trees should be left as much as feasible.
9. How much would a contractor be required to pay the government for electricity? The government normally supplies contractors reasonable amounts of electricity at no cost. The government also requests that contractors, in this case, practice conservation.
Signed
Thomas Ritz Major, USAF
Acting Chief, Engineering & Environmental Planning Branch. |
Jennifer Roberts |
| 11/12/1991 |
Enforcement Agreement or Order |
Federal Facility Agreement under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) signed for docket # 1089-07-19-120. The agreement ensures that the environmental impacts associated with past and present activities at the Base are thoroughly investigated and appropriate removal and/or remedial action(s) taken as necessary to protect human health and the environment. Elmendorf Federal Facility Agreement signed.
The general purposes of this Agreement are to: (a) Ensure that the environmental impact associated with past and present activities at the Site are thoroughly investigated and appropriate removal and/or remedial action(s) taken as necessary to protect the public health, welfare, and the environment.(b) Establish a procedural framework and schedule for developing, implementing, and monitoring appropriate response actions at the Site in accordance with CERCLA, the NCP, Superfund guidance and policy, RCRA, RCRA guidance and policy, and applicable state law.
The FFA divided the CERCLA study source areas at Elmendorf AFB into the following seven operable unites (OUs), on the basis of geographic proximity and similar source characteristics or contaminants:
- OU1 Landfills (LF05, LF07, LF13, LF59, OT56)
- OU2 Tank Spill Sites (ST20, ST41, including the ST41 Sludge Disposal Area)
- OU3 Central Containment Area (SD16, SD31, SD52, SS21)
- OU4 Northern Containment Area (SD24, SD25, SD28, SD29, FT23, SSl0)
- OU5 Southern Containment Area (ST37)
- OU6 Surface Disposal Sites (LF02, LF03, LF04, SD15, SD73, WP14)
- OU7 Limited Field Investigation (SS19)
Proposed listing on NPL was 07/14/1989 and Final listing on NPL was on 08/30/1990.
SD28 (formerly IS-5) Bldg. 43-410 floor drain. This site contains one wash rack for ground equipment. 55 gallons of PD-680 per month flow into drain and dry well.
See site file for additional information. |
Jennifer Roberts |
| 11/12/1991 |
Update or Other Action |
Jennifer Roberts Federal Facility Coordinator sent letter to Joe Williamson and Rich Howard pursuant to Section 9.1 of the Elmendorf Air Force Base Federal Facility Agreement (FFA). ADEC designates Jennifer Roberts as the Project Manager and Ron Klein as the Alternate Project Manager for all activities covered under the FFA. |
Jennifer Roberts |
| 12/30/1991 |
Update or Other Action |
EPA sent letter to AF Rich Howard and Joe Williamson. The notification will serve as an addendum to the previous letter of November 4, 1991 which designates the USEPA project managers pursuant to Section 9.1 of the Elmendorf Air Force Base (EAFB) Federal Facilities Agreement (FFA). Marcia Combes will serve a lead remedial project manager (RPM) for base-wide activities, as well as Operable Units (OUs) 2, 3, 5, 6, 7. Michele Poirier-McNeill will serve as lead RPM for OUs 1 and 4. In addition, both RPMs will serve as an alternative RPM on OUs for which they are not the lead. For communication and correspondence purposes, the lead RPM should be the point of contact, and the alternate should be copied. |
Jennifer Roberts |
| 7/17/1992 |
CERCLA PA |
Memorandum for a meeting held at CH2MHILL/ANC on July 8, 1992 subject: OU4 IRA Planning. Purpose was to discuss the preliminary results of the OU4 Limited Field Investigation (LFI) field work and reach consensus among the project managers on which OU4 source areas would be appropriate for an Interim Remedial Action (IRA). General criteria for an Interim Remedial Action (IRA):
1) contamination verified above action levels (EPA and ADEC guidance levels);
2) point source contamination defined and accessible;
3) IRA implementable;
4) IRA won't interfere with final remedy; and
5) IRA should prevent further release of contaminants.
SD28 (Building 43-410): Dry well verified and accessible at the ground surface; residual soil/gravel sampled directly; Contamination above action levels included metals and petroleum hydrocarbons; Building currently not in use; building not connected to sanitary sewer; FY94 MCP scheduled for installation of sewer to that side of Base; Building has newly installed oil/water separator (connected to 2 new USTs); dry well appears to have been taken out of service; CH2MHILL to confirm an earlier report of sludge observed in dry well; latest field observation did not confirm sludge; Consensus: IRA appropriate at this location. Potential IRA Alternatives: 1. No action. 2. Remove sand/gravel material in dry well, dry well and piping structures and disposal. 3. Remove sand/gravel material, dry well and piping, disposal, and construct surface cap. Disposal costs may be obtained through DRMO; may need to consider TCLP for metals; Need to assume certain amount of sand/gravel material for disposal in order to do cost analysis; Ultimate disposal method options under IRA quantities (for all IRAs) will be discussed in Preliminary Alternatives summary, but specific detail on each disposal method is not expected.
Note to file:
Interim Actions
The purpose of the IA-OUs at the EAFB are to achieve early actio using remedial authority at
those sites which meet the IA deneral principles that are discussed in the NCP. If at anytime the information submitted to suppo-t the IA is found to be equivalent to that obtalned during an Rl/FS and the OU is separable, then he IA may be upgraded to an early final action.
The Preamble of the NCP, 55 Federal Register 8703-8706 (March 8, 1990) states that to Implement
an early action under remedial authority, an operable unit for which an interim action is appropriate is identified. IA decisions are intended for straightforward sites that are limited in scope.
Data sufficient to support the interim action decision is extracted from the ongoing RI/FS or from previous studies and an appropriate set of alternatives is evaluated. Few alternatives and in some cases only one should be developed for interim actions. A completed basellne risk assessment generally will not be available or necessary to justify an interim action. |
Jennifer Roberts |
| 9/16/1992 |
Update or Other Action |
Revisions to the EAFB FFA SOW OUs 4 and 7 from Air Force to ADEC (J. Roberts). 1. As a result of this summer's field investigation, we request attachment 1 of the FFA be revised as follows:
a. Move FT23 from OU7 to OU4. Based on the results of the Limited Field Investigation (LFI) it appears FT23 may be a source of contamination observed in past investigations at SD24, SD25,
SD26, and SD27.
b. Move SD31 from OU4 to OU3. Geographically, SD31 is more closely aligned with the sources in OU3.
c. Move SS63 (Classic Owl) from OU4 to OU7. Currently at Classic Owl a building is under construction by the Corps of Engineers. If SS63 remains in OU4, then there could be major
conflicts which several contractors working in the area. Also by moving SS63 into OU7, we would be able to address all of the sources located north of the Elmendorf Moraine in one remedial
investigation.
d. Delete the requirement of an interim remedial action (IRA) at OU4. Based on the LFI, the remedial project managers identified the dry wells at SD24, SD28, and SD31 as potential
IRAs. However, further review of the results of the LFI, indicate only the sludge at the bottom of the dry well at these sources were sampled and no soil samples were obtained. At this
time there is no evidence of soil contamination in the immediate vicinity of the dry wells. Without additional investigation of these wells, it does not appear an IRA is warranted. Instead of an IRA, we will pursue funding to remove the sludge in each dry well.
e. Delete the requirement of an IRA at OU7. In 1988, light non-aqueous phase liquid (LNAPL) contamination was found and an IRA was put into the FFA to remove the LNAPL from this source
area. Based on two rounds of water level measurements that showed no LNAPL and soil samples collected this summer (see attachment 1), it appears that there is no reason to address the
LNAPL and we do not have enough information to address the soil contamination. Without additional investigation of this source, it does not appear an interim action is warranted.
s/s Joseph Williamson and approved by Jennifer Robers RPM ADEC.
|
Jennifer Roberts |
| 3/26/1993 |
Update or Other Action |
DOD and ADEC joint Technical Memorandum of understanding signed concerning the Base wide Groundwater (GW) signed by: ADEC Jennifer Roberts RPM and USAF Joseph Williamson Chief Environmental Programs & Restoration. Due to the base wide GW study and the FY92 field work that occurred at Operable Units (OUs) 1, 2, and 5 it appears a large portion of the GW flows into OU5 (attach. 1-contour map). Based on this fact, Elmendorf (EAFB) will move all upgradient GW into the OU5 Feasibility Study, Proposed Plan and Record of Decision (ROD). This means addressing all GW from upgradient sources (CERCLA (ST20, OUs 3 and 4) and OUs 1 and portions of OU2) and SERA) at OU5 instead of at each individual source area (see attach. 2-Area Map). Sites with free phased product would be looked at to see if there is an available technology to clean them up in a cost effective way. Soil contamination would be addressed at the source areas. NOTE: addressed at the source areas is interpreted by ADEC as removal through excavation or active treatment systems (e.g. high vacuum extraction, bioventing, etc...). |
Jennifer Roberts |
| 3/16/1994 |
Site Ranked Using the AHRM |
Initial ranking. |
Louis Howard |
| 5/3/1994 |
Site Added to Database |
BTEX/gasoline contamination. |
Louis Howard |
| 9/15/1994 |
Risk Assessment Report Approved |
Risk assessment combined with RI/FS final version received and approved. 12 constituents were identified as major contributors to groundwater risk. 8 were identified as contributors to carcinogenic groundwater risk: benzene, chloromethane, dieldrin, 1,1-dichloroethene, 1,2-dichloroethane, chloroform, trichloroethene, and carbon tetrachloride. 4 constituents were principal contributors to noncarcinogenic groundwater risk, including toluene, ethylbenzene, cis-1,2-dichloroethene, and trichloroethene. Results of the risk evaluation for soils indicated six constituents as primary contributors to the carcinogenic risk in soil, including benzo(a) pyrene, benzo(b)fluoranthene, dibenzo(a,h)anthracene, benzo(a)anthracene, PCB-1260, and benzo(k)fluoranthene. Noncarcinogenic risk in soil did not exceed an HQ of 1.0.
The results of the risk assessment indicate that each of the six soil and five of the six groundwater areas of interest have a carcinogenic risk in excess of 1.0 x 10-6 using the most conservative residential estimates. At the Asphalt Drum Storage Area, no groundwater risks were identified.
Ecological risk assessment: Ecological quotients for moose did not exceed 1.0 for moose. EQs of 1.0 were exceeded for copper and lead for meadow voles at OU4. None of these exceedances appear to be highly significant for the following reasons: the overall nature of the methodology used was conservative. In several cases the calculated doses, reference criteria, or measurement endpoints were inappropriate for this site because even normal background concentrations caused exceedances. Finally, the relatively uniform distributions of concentrations of manganese, selenium and thallium across all the sites is not typical of highly contaminated areas. |
John Halverson |
| 9/15/1994 |
Site Characterization Report Approved |
Final version of the remedial investigation/feasibility study received and approved. |
John Halverson |
| 4/11/1995 |
Proposed Plan |
Proposed plan lists Building 43-410 with Hangar 15 so future reference is to Hangar 15. Hangar 15 has groundwater listed to contain Tetrachloroethene, chloroform, chloromethane, and TCE. Soils were found not to exceed Alaska cleanup matrix criteria although low-level tar and asphalt byproducts were detected. Preferred alternative for all shallow and deep soils is institutional controls and intrinsic remediation within 3 years. The groundwater contamination is expected to be cleaned up with 7 years. |
Louis Howard |
| 10/10/1995 |
Cleanup Level(s) Approved |
In the Record of Decision the groundwater is listed to contain Tetrachloroethene (5 ug/L), chloroform, chloromethane and TCE (5 ug/L). |
Jennifer Roberts |
| 10/10/1995 |
Institutional Control Record Established |
ICs established by signing of ROD. Subsequently the AF has been able to implement these controls on soil and groundwater media for all activities by AF personnel and its contractors. Land planning department and environmental restoration staff monitor all activities on Base.
No current receptors exist for the groundwater at the Base due to the institutional controls (ICs). As a requirement of previously signed RODs for the Base, ICs have been established to restrict the use of the shallow aquifer in the outwash plain on Base. These restrictions are enforced through the Base Comprehensive Plan (BCP).
Projects and other activities are reviewed during the planning stage to ensure compliance with the BCP. In addition, construction projects and other activities also undergo an environmental review. This review helps ensures compliance with groundwater use restrictions. |
Louis Howard |
| 10/10/1995 |
Record of Decision |
ROD states all shallow and deep soils for hangar 15 will be addressed through institutional controls and intrinsic remediation for COCs.
NOTE TO FILE: § 300.430 Remedial investigation/feasibility study and selection of remedy.(a) General—(1) Introduction. The purpose of the remedy selection process is to implement remedies that eliminate, reduce, or control risks to human health and the environment. Remedial actions are to be implemented as soon as site data and information make it possible to do so. Accordingly, EPA has established the following program goal, expectations, and program management principles to assist in the identification and implementation of appropriate remedial actions.
(iii) Expectations. EPA generally shall consider the following expectations in developing appropriate remedial alternatives:
(D) EPA expects to use institutional controls such as water use and deed restrictions to supplement engineering controls as appropriate for short- and long-term management to prevent or limit exposure to hazardous substances, pollutants, or contaminants. Institutional controls may be used during the conduct of the remedial investigation/feasibility study (RI/FS) and implementation of the remedial action and, where necessary, as a component of the completed remedy. The use of institutional controls shall not substitute for active response measures (e.g., treatment and/or containment of source material, restoration of ground waters to their beneficial uses) as the sole remedy unless such active measures are determined not to be practicable, based on the balancing of trade-offs among alternatives that is conducted during the selection of remedy.
Cleanup for soils (both shallow and deep) is calculated to be 3 years and for GW estimated to take 7 years with IC/IR.
Institutional controls on land use and water use restrictions will restrict access to the contaminated GW throughout OU4 until cleanup levels have been achieved. GW will be monitored semi-annually to assess contaminant migration and timely reduction of contaminant concentrations by IR. This will include 5 year reviews to assess protectiveness of the remedial action, as long as contamination remains above cleanup levels. |
Louis Howard |
| 10/17/1996 |
Update or Other Action |
Air Force memo: Restricted Use of the Shallow Aquifer on EAFB signed by William R. Hanson P.E. GM-14 Chief Environmental Flight dated October 17, 1996 Memorandum for 3 SPTG/CEC/CEO from 3 SPTG/CEV
1) Due to the contamination and commitments to EPA/DEC the use of the shallow aquifer for any purpose on is not allowed. Attached Facilities Board minutes-03/29/1994 0930 Item 9 has Mr. William Hanson, briefing the Board on the policy to not use the shallow aquifer due to contamination. The Board approved this policy. Minutes approved by Thomas R. Case Brigadier General USAF Commander. The IRP has RODs for OUs 3 and 6 which require, the aquifer remain unused.
2) Personnel in the review process within CES must be aware of these policies and review them on a recurring basis. It is imperative this restriction be recognized and observed during engineer reviews and operations. |
Louis Howard |
| 3/13/1997 |
Update or Other Action |
UPD action added 3/13/97, based on Relative Risk Evaluation Worksheet dated 8/22/95. S&W added site description in "Comments" section. |
Louis Howard |
| 6/16/1997 |
Update or Other Action |
USAF Memorandum to ADEC regarding Clarifications to Operable Unit (OU) 2 Record of Decision (ROD). The letter is a follow-up to the discussions regarding institutional controls at OU2. The USAF hopes by this correspondence, to clarify appropriate land use controls at OU2 and setup a land use restriction method consistent with the most recent Elmendorf RODs. The OU2 ROD states that groundwater at ST41 needs remedial action and a part of the selected remedy was to restrict land use by implementing zoning controls. The Summary of the ROD on page 9-2 states that the selected remedy includes "Zoning the affected area for industrial use only, excluding the development of commercial aquaculture."
However, the Declaration of the ROD states "Zoning the affected area for undeveloped outdoor/recreational use only." In light of this contradiction and the use of "restricted use areas" under the RODs for OU3 and OU6 the USAF is providing clarification of the permissible land uses within the area affected by ST41 groundwater. The affected area should include those areas that exceed the groundwater cleanup levels established in the OU2 ROD. A map of the area currently and potentially impacted by the contaminated groundwater from ST41 is at attachment 1. This map may be revised based upon review of the contamination remaining in place, which will be conducted at least every 5 years.
While the affected area remains above cleanup levels, it will be designated as a "restricted use area" in the base Planning Office. This designation provides for recreational use of the parcel (such as cross country skiing, bicycling, etc.) and the construction of unmanned facilities (such as parking lots, storage buildings, etc. ) but prohibits the construction of any manned facilities (such as office buildings or a residence). Construction activities within the affected area of OU2 will be restricted to construction of unmanned facilities.
Furthermore no construction will be allowed which comes within five feet of the groundwater. Existing industrial uses within OU2 are allowed as they are unmanned. This description conforms to the current base land use planning terminology and is consistent with the recently signed RODs for OUs 3 and 6. Land use restrictions will be enforced by the following method. When there is a construction project on Base, the project is to be approved by the Base Planning Office. The planner will route all projects through the Environmental Management Office. The project will be disapproved if it conflicts with the above construction restrictions. The USAF believes this will be a reliable and effective means of enforcing the zoning land use restrictions imposed by the various RODs. Signed by Randy E. Honnet Colonel USAF Vice Commander. |
Louis Howard |
| 7/24/1998 |
Update or Other Action |
6/98 Remedial action report final states tetrachloroethene and trichloroethene in groundwater will be remediated in 7 years. No soils contaminated above action levels. |
Louis Howard |
| 11/8/1999 |
Update or Other Action |
The location of a former 500-gallon UST (tank 31-338) that was primarily used to store JP-4 jet fuel waste from fuel truck maintenance activities. The UST was removed in August 92, and replaced with a 1,200-gallon UST (31-338A) in an adjacent location.
The depth to groundwater in well 49WL01 located approximately 150 feet south-southwest of the site, was measured at 13.59 feet below ground surface (bgs). The depth to groundwater in the bioventing vent well was measured at 11.53 feet bgs. Shallow groundwater is not currently used as a drinking water source and is unlikely to be used as one in the future. Contaminant of concerns (COCs) with initial contamination levels are as follows:
Initial Contamination Levels for Soil Water
Diesel Range Organics (DRO) 860 mg/kg 9,700 ug/l
Gasoline Range Organics (GRO) 3,600 mg/kg 9,700 ug/l 9 Benzene .033 mg/kg 740 ug/l
Toluene 1.3 mg/kg 35 ug/l
Ethylbenzene 4.9 mg/kg 95 ug/l
Total xylenes 80 mg/kg 1,300 ug/l
STATEMENT OF BASIS-This decision is based on the following attached references:
a. Site ST71 from SERA Phase I Corrective Action Plan (CAP), Final, Apr 95
b. Alaska Department of Environmental Conservation's (ADEC) 27 Feb 97 Ltr
c. Table 4-17, Basewide Annual Groundwater Report, Final, Mar 98 (49WL01)
d. Site Closure Report for Site ST71, Nov 96 (refer to your copy)
e. Table 5-8, Basewide Annual Groundwater Report, Final, Jun 99 (49WL01)
f. Table 2-4, Basewide Monitoring OU4-Round 1, Aug 99 (49WL01)
DESCRIPTION OF THE SELECTED REMEDY-No further remedial action remedy is based on the field sampling conducted on 28 May 96 pursuant to closure of site ST71 on base. All of the laboratory analytical results for vadose zone soil were below ADEC (1995) Category A soil cleanup levels for all analytical methods. These results indicate that petroleum hydrocarbons in the vadose zone soil at the site have been remediated to the applicable matrix cleanup levels during the operation of the bioventing system.
Monitoring well 49WL01 has been added to the OPERABLE UNIT (OU)4 monitoring program. With the exception of benzene concentrations in groundwater at down gradient well 49WL01 (14.9 ug/l), GRO (930 mg/kg at 49BH07-12 and 500 mg/kg at 49BH08-13), and DRO (1,600 mg/kg at 49BH07-12) concentrations in saturated soil samples, this site meets all applicable state cleanup goals. Contaminated soil below the watertable is not effectively remediated through bioventing.
The vadose zone soil was below ADEC (1995) Category A soil cleanup levels for all analytical methods. This has allowed the bioventing system at this site to be turned off in 1997 and will be removed in the future. The groundwater contamination is under the cleanup levels in Table C using the criteria outlined by 18 AAC 75.345 (b)(2)(A)&(B). In addition, the wetland remediation system constructed on the Ship Creek flood plain prevents ST71 contamination from leaving the base property boundary. Therefore, there is no further requirement for tracking conditions at ST71. Monitoring well 49WL01 has been added to the OPERABLE UNIT (OU)4 (Basewide) monitoring program.
If any information is presented in the future that indicates contamination from this project area is present (above established cleanup levels) and/or poses a risk to the public's health or the environment, then additional assessment and corrective action may be necessary. The location of this monitoring well is useful to track trends of trichloroethene (TCE), dichloroethene (DCE), and chloride concentrations in the outwash plain. The remedy of no further remedial action under the ERP is selected because the contaminant levels at the site present no significant threat to human health or the environment; thus, no treatment is necessary. |
Louis Howard |
| 8/28/2002 |
Meeting or Teleconference Held |
STATUS MEETING MINUTES ELMENDORF BASEWIDE MONITORING PROGRAM AUGUST 28, 2002 Attendees: Joe Williamson (USAF), Cindy Hood (AFCEE), Terry Beach (AFCEE), Kevin Oates (EPA), Louis Howard (ADEC), Cory Hinds (URS), Russ Beck(URS). Agenda: • Review of soil gas surveys and new well locations • Recommendation for treatment ofTCE at OUS Seeps 9, 10, and 11 in the existing
Wetland Remediation System • Well sampling frequencies for 2003
2003 Monitoring Well Sampling Frequencies-URS presented the new proposed Basewide decision guide for determining sampling frequencies for monitoring wells. Proposed monitoring frequencies are based on position of plumes relative to environmental receptors. Plumes immediately upgradient of a receptor were proposed for annual sampling. Plume not immediately upgradient of a receptor were proposed for sampling every 2 to 5 years.
EPA pointed out that this guide is only appropriate for stable plumes and suggested that we add a box to include a decision for unstable plumes. Unstable plumes should be sampled semiannually
if upgradient of a receptor or within the early warning line in OU 5. URS presented the new sampling frequency table, which is based on plumes rather than program areas. EPA and ADEC agree that it makes sense to organize on a plume-by-plume basis instead of by program area.
The Air Force mentioned that there will be additional wells required for the early warning system at OU5, and that some of the early warning sampling will be conducted using passive diffusion bags. Use of the passive bags may mean that it is feasible to sample in the winter. EPA, ADEC, and URS agreed on modification of sampling frequencies. In general, sampling frequencies were increased when the plumes were close to a receptor (i.e., Ship Creek)
or the concentrations of contaminants were increasing.
Additional items discussed:
• WP14: Air Force mentions reducing number of wells. ADEC mentions an early warning
system. These will be discussed later.
• Air Force will investigate the floating product at OU4 West. |
Louis Howard |
| 8/29/2003 |
Site Number Identifier Changed |
Changed Work plan from X1 to X9 due to presence of hazardous substances in the GW above cleanup levels. |
Louis Howard |
| 3/21/2005 |
Update or Other Action |
2004 Phase I Remedial Process Optimization (RPO) Annual Report (Draft Final) received for OU 4 East Plume. OU 4 East consists of SD28 (Bldg. 43-410), SD29 (Bldg. 43-450 Hangar 15) and SS10 (Asphalt Drum Storage Area). There is one impending issue to report at the OU 4 East Plume. The one well at which this plume is monitored, IS6-01, is damaged and is no longer serviceable. During well inventory efforts conducted during 2004, a 0.5-inch-diameter groundwater indicator probe was unable to reach water. The riser pipe is cracked roughly 5 feet bgs, and the probe could go no deeper than this depth.
As was noted previously, well IS6-01 is damaged, no longer serviceable, and in need of a replacement. No more than one well is required to monitor this plume. It is recommended that a new well be installed within 5 feet of the current location of IS6-01.
|
Louis Howard |
| 2/26/2007 |
Exposure Tracking Model Ranking |
|
Louis Howard |
| 3/7/2008 |
Update or Other Action |
Zone 2 Remedial Process Optimization Report received. The selected remedy for SD28 includes LUCs. These LUCs are preventing human and environmental receptors form being exposed to any potential contaminated groundwater. Remediation workers are adequately protected. The 2003 five-year review (USAF, 2003a) found that the remedy is functioning as intended in the OU 4 ROD;
exposure assumptions, toxicity data, cleanup levels, and RAOs used at the time of the remedy selection are still valid.
Monitoring data collected during the RI/FS indicate that groundwater TCE and PCE concentrations are below the ROD specified cleanup criteria of 5 µg/L (USAF, 1995a). Even though no groundwater contamination is present, ROD-specified LUCs are enforced through the Elmendorf AFB 3rd Wing Dig Permit process. Annual LUC inspections are performed and documented in accordance with the Final Land Use Control Management Plan (USAF, 2003c).
Because groundwater concentrations at SD28 meet cleanup criteria, no further remedial action is necessary to ensure protectiveness based on the RAOs. Discussion should begin with the regulators to move toward a No Further Action (NFA) determination. |
Louis Howard |
| 10/15/2008 |
Update or Other Action |
5 YR Review
No wells associated with SD28 were monitored.
SD28 well IS5-01 was last sampled in 1993, and concentrations of the COCs TCE and PCE were below cleanup levels. COC concentrations in nearby wells OU4-E1 (upgradient of SD28) and OU4-E3 (downgradient of SD28 and SD29) were similarly below cleanup levels. Well OU4-E3 was last monitored in 2002. Based on the available data, groundwater at SD28 has met cleanup levels for all COCs and the site should be closed out.
Recommendations for changes to the OU4 monitoring program include:
Prepare a memorandum to the site file documenting that groundwater meets cleanup levels at SD28 and recommend NFA for this site.
Site Inspection
OU4 (SD24, SD25, SD28 and SD29). All active monitoring wells were located and were in good condition. There are no active monitoring wells for SD28. There was no evidence of unauthorized wells or site disturbance.
Recommendations/Follow-up Actions
Prepare a Site Closure report documenting that groundwater meets cleanup levels at SD28 and
recommend NFA for this site.
The remedy at site SD28 is protective of human health and the environment. Groundwater
samples from the time of the ROD show that no contamination above background levels/regulatory cleanup levels remains and the site is acceptable for UU/UE. |
Louis Howard |
| 3/17/2009 |
CERCLA ROD Periodic Review |
Cover letter to the EPA's Five-Year Review signature sheet sent to Richard J. Walberg, Colonel, US Air Force Vice-Commander from EPA Region 10 Office of Environmental Cleanup Daniel D. Opalski, Director. The Environmental Protection Agency (EPA) has completed their review of the third Five-Year Review report for the United States Air Force (USAF) Elmendorf Superfund site, in Anchorage Alaska.
EPA reviewed this report for technical adequacy, accuracy, and consistency with EPA guidance. In general, EPA agrees with the protectiveness determinations in this report. However, I understand that all parties to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 120 Federal Facility Agreement (FFA) are aware of a potential new source that has not been fully characterized, namely SS-022. It is also my understanding that while the Five-Year Review identifies this potential new source, the USAF has not adequately discussed the interim measures it has already taken to ensure protectiveness as site characterization proceeds, such as Institutional Controls (ICs) at SS-022 and the ongoing Remedial Investigation.
Therefore, we recommend that within ninety (90) days (by June 15, 2009), USAF supplement the Site File and Administrative Record with a Memorandum to document the ICs (e.g., installation of a fence, signage, and notation on the Environmental Restoration Program Atlas) that have been implemented for the protection of human health and the environment at SS-022. The Memorandum should also mention the Installation-wide ICs (including restriction of ground water use) already in place.
In addition, EPA agrees with USAF's recommendation for further action at the OU-l landfill area for the trichloroethylene (TCE) groundwater contamination, and requests that the Program Managers meet to discuss the timeline for completion of the groundwater contamination characterization and establish deadlines and, as appropriate, target dates for subtasks, as required under the FFA.
|
Louis Howard |
| 4/14/2010 |
Update or Other Action |
This annual report includes a qualitative evaluation of the 2009 groundwater analytical data to
determine if the current conditions at the Zone 2 potentially warrant changing the 2007 RPO
category for each site. The next detailed RPO evaluation is scheduled for 2012.
Field activities performed during 2009 at Zone 2 included water level measurements; groundwater sampling; operation, maintenance, and monitoring (OM&M) of the bioventing system at Sites FT23 and ST32; decommissioning of the FT23 bioventing system; soil, groundwater, and vapor intrusion investigations at FT23; a groundwater investigation at SS43; soil and groundwater investigations at ST32; monitoring well inspections and surveys at ST32; well abandonment; well maintenance; well flagging; land use control (LUC) inspections; and waste management.
The 2007 RPO evaluation identified Site SD28 as a Green priority site because no groundwater contamination above the cleanup levels has been identified (USAF, 2008). There is no indication that the Green priority designation for Site SD28 should be revised. As recommended in the RPO report, a discussion with the regulators should be initiated regarding a no further action determination for this site. |
Louis Howard |
| 4/28/2010 |
Update or Other Action |
Memorandum for ADEC. SUBJECT: Response to ADEC Comment on Draft 2009 Zone 1 Field Activities Report (Ref: ADEC Memo, 12.Mar 10)
1. This memorandum is in response to ADEC's concern as to why diesel-range organics (DRO) and gasoline-range organics (GRO) at select groundwater plumes were not sampled in 2009 as
previously agreed in a January 14, 2003 meeting. Specifically, ADEC's comment (Attachment 1) is in reference to Section 3.7.1 Implications of Contaminant and Geochemical Monitoring, Page 3-17 of the draft 2009 Zone 1 Field Activities Report, which stated:
"The text states: When these parameters were monitored from 1999 to 2007, GRO concentrations in this monitoring well exceeded cleanup levels while DRO concentrations hovered near the cleanup level. ADEC requests the Air Force provide an explanation or a memorandum to the site file as an appendix to the document on why DRO and GRO were eliminated from the monitoring program as previously agreed to in a January 14, 2003 meeting with ADEC, USAF and EPA."
2. The analytes in question were not included in the Zone 1 groundwater monitoring program
for FY09 due to an administrative oversight. The agreement to monitor for DRO and GRO was
captured in meeting minutes (Attachlnent 2), not in a more formal mechanism such as a decision
document or memorandum to the·site file. In preparation for programming of project
requirements, we reviewed the governing documents for the Zone 1 sites. None of the governing
documents for Zone 1 sites identified GRO/DRO as a contaminant ofconcem (COC); therefore,
GRO/DRO sampling was not programmed or conducted in 2009.
3. The U.S Air Force agrees with ADEC's request to continue sampling for diesel-range organics (DRO) and gasoline-range organics (GRO) for CERCLA sites with fuel-related plumes. Minutes of a 14 Jan 03 meeting with EPA, ADEC and DRS, provided with the above referenced ADEC memo, documents that the Air Force agreed to add DRO/GRO into the sampling program under the following conditions:
a. The decision will be documented in the 5-Year Review. The addition of DRO/GRO to the program should be introduced in the 5-Year Review under· mention of new issues affecting protectiveness.
b. The Air Force will NOT add DRO/GRO as a CERCLA ARAR, but will compare DRO/GRO results to ADEC cleanup levels in the annual reports and will discuss in subsequent 5-Year Reviews. The benefit of this is that if CERCLA COCs meet ARARs, the Air Force can achieve a partial delisting.
c. The Air Force will add DRO and GRO to the suite of analyses at monitoring wells associated with fuel plumes starting in 2004.
d. The Air Force will not pursue a decision document with ADEC on DRO/GRO until more data is gathered on the extent of the problem.
e. Until a decision document is signed with ADEC, GRO and DRO concentrations will be compared to ADEC regulations in 18 AAC 75 (Table C, Groundwater Cleanup Levels; 1,500 ug/L for DRO, 1,300 ug/L GRO).
f. Sampling frequency for DRO/GRO will follow the latest Decision Guide for Sampling Frequency (see 2002 Basewide Annual Report). "Immediately up gradient" means within a 2-year warning line, similar to that generated for OU5.
g. ADEC GRO/DRO criteria apply to groundwater, not to seeps which daylight as surface water. Criteria in 18 AAC 70 (TAH, TAqH) apply to surface water.
4. The fact that these analytes were not included in the Zone 1 groundwater monitoring program
for FY09 is attributed to an oversight. The USAF will add DRO/GRO into the suite of analyses
at monitoring wells associated with fuel-related plumes for Zone 1 (LF04 South and WP14) and
will prepare a memo to the site file to prevent this type of oversight from occurring in the future.
The USAF strategy will be to compare DRO/GRO and total aromatic hydrocarbon (TAH)/total
aqueous hydrocarbon (TAqH) sample results as contaminants of interest with current ADEC
regulations in 18 AAC 75 - Table C - Groundwater Cleanup Levels and 18 AAC 70 for surface
water. Should you have any questions, please feel free to contact me at (907) 552-2875.
Signed Gary Fink YF-02 Chief, Environmental Restoration. |
Louis Howard |
| 1/24/2011 |
Update or Other Action |
Staff received the 2010 Zone 2 Mgt. Area Annual Report. This annual report presents a description of the activities performed in 2010 at the Zone 2 Management Area at Joint Base Elmendorf-Richardson (JBER), Alaska. This document describes field activities and pertinent observations, presents analytical data, and provides recommendations for the Zone 2 Management Area, which now includes Sites ST48 and ST68. Beginning in 2010, Sites ST48 and ST68 have been included in reports related to the Zone 2 Management Area (rather than the Zone 3 Management Area) because the boundary between the Zone 2 and Zone 3 Management Areas was revised during the 2009 field season.
No field work was performed at Site SD28 in 2010.
The 2007 RPO evaluation identified Site SD28 as a Green priority site because no groundwater contamination above the cleanup levels has been identified (USAF, 2008a). There is no indication that the Green priority designation for Site SD28 should be revised. As recommended in the RPO report, a discussion with the regulators should be initiated regarding a no further action (NFA) determination for this site.
|
Louis Howard |
| 1/28/2011 |
Update or Other Action |
Staff received the 2010 Annual Land Use Control (LUC) Monitoring Letter for DP98 and Operable
Units (OUs) 1,2,4,5, and 6. References: (a) DP98 Record of Decision, Section 12.2.3.4, dated May 2004, (b) OU6 Explanation of Significant Differences, Section 4.3.1.3, dated Mar 2007, and
(c) Memorandum to the Site File for OUs 1,2,4, and 5, Section 4, dated Jan 2010.
This letter serves as the annual monitoring report on the status of LUCs in place at DP98 and
at OUs 1,2,4,5 and 6.
Groundwater - Restrict access to the contaminated groundwater throughout OU 4 until cleanup levels have been achieved. OU4 is designated "Airfield Use Area" for aircraft operations and maintenance, to include active and inactive runways, taxiways, and parking aprons for aircraft.
Soil- Institutional controls on land use (also called LUCs) will continue to restrict access
to the contaminated shallow soils throughout OU 4 until cleanup levels have been achieved.
Evaluation - A land use control inspection was performed and land use controls are in place and continue to be effective at SD28.
The Air Force ensures compliance with LUCs by conducting periodic monitoring and completing site inspections. Separate controls are in place and enforced by the Air Force to prevent inappropriate soil and groundwater exposure at these sites. The Air Force currently requires all proj ects resulting in soil disturbance of greater than four inches below ground surface
to follow 3r Wing Instruction 32-1007, Safeguarding Utilities from Damage, dated 17 Aug 07
and 3rd Wing Instruction 32-7003, Land Use control Management, dated 16 Feb 07. Both instructions require the proponent to obtain an approved Base Civil Engineer Work Clearance
Request (3 WG Form 3) prior to conducting work on the Base. |
Louis Howard |
| 7/15/2011 |
Update or Other Action |
Draft Work Plan Environmental Remedial Action-Operations & LTM & Maintenance received.
The purpose of this project is to perform RA-O & LTM activities for several JBER Programs. These programs include sites distributed across both JBER-Elmendorf & JBER-Richardson. This Work Plan addresses remedial activities in JBER-Elmendorf Zone 1, Zone 2, & Zone 3 Management Areas, JBER-Elmendorf Compliance Restoration Program (CRP) sites, the JBER Elmendorf Operable Unit (OU) 1 Landfill, JBER-Richardson Multiple Installation Restoration Program (IRP) Sites, & JBER-Richardson Poleline Road & OUE Armored Vehicle Maintenance Area (AVMA).
Currently there are ten active sites within the Zone 2 Management Area: FT23, SD15, SD24, SD25, SD28, SD29, SS43, ST32, ST48, & ST68. The OU4 ROD (USAF, 1995a) specifies the selected remedy for Sites FT23, SD24, SD25, SD28, & SD29. Currently, LUCs are used at all OU4 sites until cleanup levels are met, & GW monitoring is performed at Sites FT23 & SD25. At Site SD15, 149 an ESD; to the OU 6 ROD (USAF, 1997) transitioned the remedy for this site to monitored natural attenuation (MNA). The remedial approach for Site SS43 is described in the State-Elmendorf Environmental Restoration Agreement (SERA) Phase I Corrective Action Plan, & currently consists of natural attenuation with free product removal. The selected remedy for soils with contamination in excess of cleanup levels at Site ST32 is limited hot spot removal with off-site low-temperature thermal desorption.
A final remedy for GW at Sites ST32 & ST48 has not been established. The remedy for ST68 includes MNA & LUCs specified in a DD that was finalized in 2007. Impacted media at the Zone 2 Management Area sites includes soil & GW. COCs identified for Zone 2 sites include trichloroethene (TCE); tetrachloroethene (PCE); 1,1,1-trichloroethane (1,1,1-TCA); 1,1,2-TCA; 1,2-dichloroethane (1,2-DCA); 1,1-dichloroethene (1,1-DCE); 1,2-DCE; 1,1,2,2-tetrachloroethane (1,1,2,2-PCA); benzene, toluene, ethylbenzene, & total xylenes (BTEX); DRO; & gasoline-range organics (GRO).
The overall objectives of RA-O activities within the Zone 2 Management Area are to monitor the rate of natural attenuation within GW plumes, determine the effectiveness & protectiveness of the site remedies (currently MNA for all sites), & manage all waste according to state & federal regulations.
Site SD28 is located at Building 16710 (formerly Building 43-410), which was used as a wash rack for ground refueling equipment. Wash water contaminated with waste engine oil, hydraulic
fluid, and JP-4 was produced during facility operations. The wash water and spent petroleum
distillate (non-halogenated) solvent were discharged to a dry well until 1979. After 1979, spent
solvent and other wastes from facility operations were recycled or disposed through the Defense
Reutilization and Marketing Office. Site SD28 was investigated, and remedies were implemented as part of the OU4 investigation and cleanup in association with Site SD29 (formerly Hangar 15). A ROD was signed for OU4 in 1995 (USAF, 1995a). No COCs were identified for soil; the COCs in groundwater at Site SD28 include PCE and TCE. Analysis of groundwater samples collected from 1988 to 1993 did not detect PCE or TCE at groundwater monitoring well IS5-01 and this well was abandoned.
The Zone 2 Management Area sites are located throughout the central portion of JBER-Elmendorf. The southern boundary of Zone 2 is parallel to the southern edge of the east/west instrument runway. The WP presents the site locations, associated sources, & plumes. Ten sites & 12 GW plumes are located within this management area, as follows (analytes shown exceeded cleanup levels during the most recent monitoring event):
• Site FT23 (2 plumes) - TCE & PCE
• Site SD15 - benzene & TCE
• Site SD24 - benzene
• Site SD25 - toluene & benzene
• Site SD28 - TCE & PCE
• Site SD 29 - TCE & PCE
• Site SS43 - benzene, gasoline range organics (GRO), DRO
• Site ST32 (2 plumes) - benzene, GRO, & DRO
• Site ST48 - GRO
• Site ST68 (2 plumes) - benzene & GRO |
Louis Howard |
| 2/2/2012 |
Update or Other Action |
Memorandum for 2010 Annual Land Use Control (LUC) Monitoring Letter for DP98 and OUs 1, 2, 4, 5, and 6.
References:
(a) DP98 Record of Decision, Section 12.2.3.4, dated May 2004
(b) OU6 Explanation of Significant Differences, Section 4.3.1.3, dated Mar 2007
(c) Memorandum to the Site File for OUs 1,2,4, and 5, Section 4, dated Jan 2010
1. This letter serves as the annual monitoring report on the status of LUCs in place at DP98 and
at OUs 1,2,4,5 and 6. The specific LUCs in place at each site are provided below. An
evaluation of the implementation of these requirements is provided in bold following each
specific LUC.
OU4:
Site SD28
Groundwater - Restrict access to the contaminated groundwater throughout OU 4 until cleanup levels have been achieved. OU4 is designated "Airfield Use Area" for aircraft operations and maintenance, to include active and inactive runways, taxiways, and parking aprons for aircraft.
Soil - Institutional controls on land use (also called LUCs) will continue to restrict access
to the contaminated shallow soils throughout OU 4 until cleanup levels have been achieved.
Evaluation - LUCs are in place and continue to be effective at SD28. A land use control inspection was accomplished in Oct 2011. The inspection forms will be presented in Appendix B of the 2011 Zones 1, 2, and 3 Mgt. Area Annual Report.
2. The Air Force ensures compliance with LUCs by conducting periodic monitoring and completing site inspections. Separate controls are in place and enforced by the Air Force to prevent inappropriate soil and groundwater exposure at these sites. The Air Force currently requires all projects resulting in soil disturbance of greater than four inches below ground surface to follow 3 Wing Instruction 32-1007, Safeguarding Utilities from Damage, dated 20 Aug 10 and 673d Wing Instruction 32-7003, Land Use control Management, dated 19 May 2011. Both instructions require the proponent to obtain an approved Base Civil Engineer Work Clearance Request (3 WG Form 3) prior to conducting work on the Base. |
Louis Howard |
| 4/10/2012 |
Update or Other Action |
Draft 2011 Annual Report for Zones 1, 2, and 3 received.
A groundwater sample was collected from well SD28MW-01 on 21 November 2011 and PCE and TCE were not detected in the sample.
Summary & Recommendations
The 2007 RPO evaluation identified Site SD28 as a Green priority site because no
groundwater contamination above the cleanup levels has been identified (USAF, 2008g). There is no indication that the Green priority designation for Site SD28 should be revised. As recommended in the RPO report, a discussion with the regulators should be initiated regarding a no further action determination for this site. |
Louis Howard |
| 3/1/2013 |
Institutional Control Update |
2012 Annual LUC IC Monitoring memorandum received.
This letter serves as the annual monitoring report on the status of LUCs in place on JBER Elmendorf at DP98 and OUs 1, 2, 4, 5 and 6. The specific LUCs in place at each site are
provided below. An evaluation of the implementation of these requirements is provided in bold
following each specific LUC.
Groundwater - Restrict access to the contaminated groundwater throughout OU 4 until cleanup levels have been achieved. OU4 is designated "Airfield Use Area" for aircraft operations and maintenance, to include active and inactive runways, taxiways, and parking aprons for aircraft.
Soil - Institutional controls on land use (also called LUes) will continue to restrict access
to the contaminated shallow soils throughout OU 4 until cleanup levels have been achieved.
Evaluation -Inspection conducted on 26 Sep 12 and LUCs are in place and continue to be effective at SD28. |
Louis Howard |
| 4/1/2013 |
CERCLA ROD Periodic Review |
JBER-Elmendorf Fourth Five-Year Review received. The remedy at site SD028 is protective of human health and the environment. Groundwater samples from the time of the ROD show that no contamination above background levels/regulatory cleanup levels remains and the site is acceptable for UU/UE.
At SD028, non-detectable concentrations of COCs were exhibited by samples collected from
monitoring well IS5-01 from 1988 to 1993. Therefore, this well was subsequently abandoned.
Monitoring well SD28MW-01 was installed at the site in 2011 to evaluate for concentrations
of COCs remaining in the groundwater. Samples collected from SD28 MW-11 exhibited nondetectable
concentrations of COCs (PCE and TCE). Additional sampling is recommended at SD028 to ensure that two consecutive rounds of clean groundwater samples are collected prior to requesting a status of no further remedial action for groundwater.
Conduct two rounds of groundwater sampling at SD028. If two consecutive rounds of sampling indicate groundwater is below cleanup levels identified in the ROD, the USAF will request no further remedial action for groundwater. |
Louis Howard |
| 9/28/2016 |
Update or Other Action |
Staff commented on the interim remedial action completion report. Main comments were regarding a removal action mentioned in the 1992 limited field investigation but not reflected in the draft document. Also other comments were made regarding the 1993 soil gas results for TCE and PCE within 100' radius of the Northeast/Northwest portion of Bldg. 16710. Staff requested soil gas sampling, sub slab soil gas sampling and indoor air testing at bldg. 16710 in response to the historical results of TCE and PCE in the soil gas and the 2012 EPA OEA TCE toxicity memorandum.
See site file for additional information. |
Louis Howard |
| 4/13/2017 |
Update or Other Action |
Final Interim Remedial Action Completion Report received for SD029 Operable Unit 4. Groundwater (GW) has been monitored over time at Site SD028 using monitoring well IS5-01 and SD28MW-01. GW results from monitoring well 420WL-01 (Site 420WL-01) were also below all applicable cleanup levels. Concentrations of COCs from these wells have always been reported at less than the ROD cleanup level of 5 µg/L. The remediation phase at a monitoring well is typically complete when the data collected demonstrate that the groundwater has reached the cleanup level for COCs. USEPA recommends evaluating COC concentration levels on an individual well-by-well basis to assess whether aquifer restoration is complete.
Because soil vapor concentrations were not identified as COCs in the OU 4 ROD, it is recommended that a new two-party site be opened for Building 16710 (Formerly Building 43-410). The site should be reassessed for shallow soil gas, sub-slab soil gas and indoor air sampling at Building 16710 for evaluation of the vapor intrusion pathway with a bias towards the vicinity of the historic soil gas sampling locations near the north side of the building (ES=20E, ES-20F, ES-20G).
See site file for additional information. |
Louis Howard |
